1. Field of the Invention
The present invention relates to a matrix sensing apparatus, and more particularly, to a matrix sensing apparatus with architecture having reduced quantity of required sensing lines.
2. Description of the Prior Art
Because liquid crystal display (LCD) devices are characterized by thin appearance, low power consumption, and low radiation, LCD devices have been widely applied in various electronic products such as multimedia playbacks, mobile phones, personal digital assistants (PDAs), computer monitors, or flat panel televisions. Furthermore, the LCD device having touch panel as input interface for a user to interact with the electronic product has gained popularity. That is, the LCD touch panel is applied to more and more electronic appliances for providing a friendly interface. In general, the LCD touch panels are primarily classified into the resistive touch panels and the capacitive touch panels. The resistive touch panel positions a touched position according to related voltage drops changing in response to the touched position. The capacitive touch panel normally comprises a plurality of sensing capacitors, and the touched position can be positioned by analyzing the changing of capacitance of the sensing capacitor corresponding to the touched position.
FIG. 1 is a structural diagram schematically showing a prior-art matrix sensing apparatus for use in an LCD touch panel. As shown in FIG. 1, the matrix sensing apparatus 100 comprises a driving circuit 110, an analog multiplex unit 120, an analog-to-digital conversion unit 130, a micro-controller unit 140, a plurality of driving lines 115, a plurality of sensing lines 125, and a matrix sensing region 190. The matrix sensing region 190 comprises a plurality of sensing areas 150. Each sensing area 150 comprises a sensing unit 151 and a readout transistor 153. The readout transistor 153 is employed to control the output of sensing signals generated by the sensing unit 151 based on a driving signal furnished to the gate of the readout transistor 153 via a corresponding driving line 115. As shown in FIG. 1, each sensing line 125 is coupled to only one column of sensing units for outputting the sensing signals generated. In other words, there is one dedicated sensing line 125 disposed for each column of sensing units. Consequently, a tremendous amount of the sensing lines 125 is required for outputting sensing signals in the matrix sensing apparatus 100, which leads to high circuit layout complexity and makes a negative factor for achieving low-cost and high-resolution panel displays.